We use Random Access Machines (RAM) with addition and uniform cost measure as a
model of computation. For further details on this model and its use in logic
see [1]}. In the sequel we assume that the input
relational structure comes with a linear order on the domain. If not, we use the
one induced by the encoding of the database as a word. Whenever we iterate
through all nodes of the domain, the iteration is with respect to
the initial linear order.
